Lubricating structure for static hydraulic continuously variable transmission

ABSTRACT

A lubricating structure for a static hydraulic continuously variable transmission includes a central oil path axially formed at a center of a shaft of the transmission. A circumferential oil path is arranged at an inner circumferential part of a retainer between the retainer and an outer circumferential part of the transmission shaft. A diametrical oil path is in communication with the circumferential oil path and the central oil path of the shaft of said transmission. The diametrical oil path is provided with an orifice. A lubricant oil ejection hole is arranged at the retainer to eject lubricant oil from the circumferential oil path.

CROSS-REFERENCE TO RELATED APPLICATIONS

This nonprovisional application claims priority under 35 U.S.C. § 119(a)on Patent Application No. 2005-037265, filed in Japan on Feb. 15, 2005,the entirety of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a lubricating structure for a statichydraulic continuously variable transmission. More particularly, thepresent invention relates to a structure of an oil path for ejectinglubricant oil from a shaft of the transmission to a rotary sliding partsuch as a slant plate within the static hydraulic continuously variabletransmission.

2. Description of Background Art

In the background art static hydraulic continuously variabletransmission, there were provided a plurality of diametrical lubricantoil ejection holes directed from the central oil path of the shaft ofthe transmission axially formed at the center of the shaft of thetransmission toward the outer circumference of the shaft of thetransmission in order to eject lubricant oil from the shaft of thetransmission to a rotary sliding part such as a slant plate (seeJapanese Application No. 54734/2002 (FIG. 2), and Japanese ApplicationNo. 100909/1997 (reference numeral 77 in FIG. 2), for example). Thelubricant oil ejection hole is a hole having a relatively smalldiameter. As described above, the arrangement of a plurality of holes ofsmall diameter at a thick-wall part of the shaft of the transmissioncaused its productivity to be reduced. Therefore, a fine diameter holecould not be attained and more than the required oil was supplied. Inaddition, even if a hole of fine diameter could be machined, the numberof holes that feed oil to an appropriate location needed to beincreased. This was not preferable due to the necessity of increasing avolume of the oil pump.

SUMMARY OF THE INVENTION

The present invention provides a structure of a lubricant oil ejectionoil path having a high set degree of freedom of the lubricant oilejection hole that can be efficiently manufactured.

The present invention overcomes the aforesaid problems and a firstembodiment of the present invention is directed to a lubricatingstructure for a static hydraulic continuously variable transmission,wherein a hydraulic circuit comprised of a high pressure hydraulic pathfor feeding working oil from a hydraulic pump to a hydraulic motor and alow pressure hydraulic path for feeding working oil from said hydraulicmotor to said hydraulic pump is constituted between said hydraulic pumpand said hydraulic motor and at the same time a cylinder member storingsaid hydraulic pump and said hydraulic motor is fixed to a shaft of thetransmission by a cotter pin and a retainer for depressing said cotterpin, said lubricating structure comprising: a central oil path of theshaft of the transmission axially formed at the center of the shaft ofsaid transmission; a circumferential oil path arranged at the innercircumferential part of said retainer between it and the outercircumferential part of the shaft of said transmission; a diametricaloil path in communication with said circumferential oil path and thecentral oil path of the shaft of said transmission and provided with anorifice; and a lubricant oil ejection hole arranged at said retainer toeject lubricant oil from said circumferential oil path.

A second embodiment of the present invention is directed to alubricating structure for a static hydraulic continuously variabletransmission, wherein the circumferential oil path arranged at the innercircumferential part of said retainer forms an annular shape, there isprovided one diametrical oil path having an orifice communicating withsaid circumferential oil path and the central oil path of saidtransmission and there are provided a plurality of said oil ejectionholes.

In the first embodiment of the present invention, the orifice arrangedat the diametrical oil path is used for controlling a flowing-out amountof the lubricant oil and only a part of the diametrical oil path ofrelatively large diameter of which machining is easily carried out isapplied as an orifice. Therefore, machining can be carried out moreeasily as compared to that of arranging the diametrical lubricant oilejection hole of small diameter of the background art. Since thelubricant oil ejection hole is arranged at the extremity end of the oilpath of which oil volume is controlled with the orifice, a degree offreedom is produced for setting items such as an angle, direction andnumber of the holes or the like and a lubricating characteristic of theslant plate and the like is improved. Since the lubricant oil ejectionhole is a fine diameter lubricant oil ejection hole arranged at athin-walled retainer, manufacturing is easily carried out.

In the second embodiment of the present invention, one orifice isprovided for adjusting an amount of supplied oil. Therefore, an orificediameter can be increased and then a machining characteristic and acontrolling characteristic of the oil amount can be improved. Since thelubricant oil ejection hole can be arranged to be communicated with theannular circumferential oil path, there can be provided a plurality oflubricant oil ejection holes.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus are not limitativeof the present invention, and wherein:

FIG. 1 is a side view of the motorcycle 1 including the power unit 2 ofthe embodiment of the present invention;

FIG. 2 is a left side view of the power unit 2 mounted in themotorcycle;

FIG. 3 is a cross-sectional cutaway view along lines III-III of FIG. 2;

FIG. 4 is a cross-sectional view along IV-IV of FIG. 2;

FIG. 5 is a vertical cross-sectional view of the static hydrauliccontinuously variable transmission T;

FIG. 6 is a cross-sectional view of an essential section of the statichydraulic continuously variable transmission T showing the vicinity ofthe distributor valve 160;

FIGS. 7(a) and 7(b) are views of the cotter pin 151, wherein FIG. 7(a)is a front view, and FIG. 7(b) is a cross-sectional view along the line7(b)-7(b) in FIG. 7(a);

FIGS. 8(a) and 8(b) are views of the retainer ring 152, wherein FIG.8(a) is a front view, and FIG. 8(b) is a cross-sectional view along theline 8(b)-8(b) in FIG. 8(a);

FIGS. 9(a) and 9(b) are views of the C clip 153, wherein FIG. 9(a) is afront view, and FIG. 9(b) is a cross-sectional view along the line9(b)-9(b) in FIG. 9(a);

FIG. 10 is a vertical cross-sectional view of an essential section ofthe static hydraulic continuously variable transmission T showing thevicinity of the centrifugal governor clutch C; and

FIG. 11 is a vertical cross-sectional view of an essential section ofthe static hydraulic continuously variable transmission T showing thesupply passages for the operating fluid and the lubricant fluid.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described with reference to theaccompanying drawings, wherein the same or similar elements have beenidentified by the same reference numerals. FIG. 1 is a side view of themotorcycle 1 containing the power unit 2 of an embodiment of the presentinvention. A pair of main frames 4 connect to the head pipe 3 and slopedownwards to the rear. A pair of sub frames 5 slope downwards from thelower section of the head pipe 3 and bend rearwards. A tip of the subframes 5 connects to the rear end of the main frame 4.

A power unit 2 includes an internal combustion engine 6 and atransmission 7, and is mounted in a generally triangular space formed bythe main frame 4 and the sub frame 5 as seen from the side. A front fork8 is supported to allow rotation in the head pipe 3. The steering handle9 is mounted on the top end of the front fork 8, and a front wheel 10 isaxially supported by the bottom end. A pair of rear forks 11 aresupported on their forward end by the rear section of the main frame 4and are capable of swinging upward and downward. A rear suspension (notshown in drawing) is mounted between the rear end of the main frame 4and the center section of the rear fork 11. A rear wheel 12 is axiallysupported on the rear end of the rear forks 11.

The internal combustion engine 6 is a water-cooled V-type two-cylindercombustion engine with the cylinders opening in a V-shape towards thefront and rear. The crankshaft of the internal combustion engine 6 isperpendicular to the forward direction of the vehicle, and is installedfacing towards the left and right of the vehicle. The transmission shaftof the transmission 7 is parallel to the crankshaft. The rear wheeldrive shaft (not shown in drawing) is connected to the connecting shaft85 (FIG. 2) perpendicular to the output shaft of the transmission, andextends to the rearward of the vehicle, reaching and driving therotating shaft of the rear wheel 12.

An exhaust pipe 13 is connected to the exhaust port and is installedfacing the front and rear of the two vehicle cylinders. The exhaust pipe13 extends forwards of the internal combustion engine 6, and extendsunder the transmission 7 extending to the frame rear section. Theexhaust pipe 13 connects to the exhaust muffler 14. A fuel tank 17 ismounted on the upper section of the (main) frame 4, and a seat 18 ismounted to the rear. The internal combustion engine 6 is thewater-cooled type, and cooling water having a temperature that risesduring the process of cooling the cylinder and oil is cooled in theradiator 19 installed on the front end of the sub frame 5.

FIG. 2 is a left-side view of the power unit 2 mounted on themotorcycle. The arrow F indicates the front during installation in theframe. The front side cylinder 24F and the rear side cylinder 24Rpossess the same internal structure so the cross-section of only therear side cylinder 24R is shown. The crankcase rear section shows thestate with the left crankcase cover removed and shows the positions ofthe main internal rotating shafts and gears and sprockets.

FIG. 3 is a cross-sectional view taken along lines III-III of FIG. 2.This figure is a cross-sectional view including the rear side cylinder24R and the crank shaft 30 and the transmission shaft 100 of the statichydraulic continuously variable transmission T. The rear side cylinder24R is a cylinder holding the piston 33 connecting to the left sidecrankpin 31.

The main components of the power unit 20 in FIG. 2 and FIG. 3 are thecrankcase 20 comprised of a left crankcase 20L and a right crankcase20R, a left crankcase cover 21L, a right crankcase cover 21R, and acylinder block 25, a cylinder head 26 and a cylinder head cover 27respectively installed with the front side cylinder 24F and the rearside cylinder 24R. The following description of the cylinder sections isbased on the rear cylinder 24R.

In FIG. 3, the crankshaft 30 is supported to allow free rotation by theleft side bearing 28 and the right side bearing 29 held in theleft/right crankcases 20L and 20R. A connecting rod 32 and a piston 33are connected to the left side crankpin 31 on the crankshaft 30, and thepiston 33 is held to allow sliding movement in the cylinder hole 34 ofthe cylinder block 25. A combustion chamber 35 is formed in the sectionfacing the piston 33 of the cylinder head 26. A spark plug 36 isinserted through the wall of the cylinder head 26, and the spark plugtip enters the combustion chamber 35, and the spark plug rear end isexposed externally.

In FIG. 2, an exhaust port 40 and an intake port 41 are connected to thecombustion chamber 35. The exhaust port 40 extends forwards in the frontside cylinder 24, and rearward in the rear side cylinder 24R. The intakeport 41 extends upwards for either cylinder in the space between bothcylinders. The exhaust port 40 contains an exhaust valve 42, and theintake port 41 contains an intake valve 43. A camshaft 44 is installedinside the cylinder head cover 27. An exhaust rocker arm shaft 45, andan intake rocker arm shaft 46 are installed above the camshaft 44. Theexhaust rocker arm 47 and the intake rocker arm 46 installed on thesearm shafts are driven by the cam 44 a, 44 b of the camshaft 44. Therocker arms press the stem of the intake valve 43 and the exhaust valve42 to drive each valve to open or close. In FIG. 3, the camshaft 44 isdriven by a camshaft drive chain 51 hooked on the camshaft drivesprocket 50 installed in the crankshaft 30 and the camshaft auxiliarysprocket 49 installed on the end of the camshaft 44.

In FIG. 2, a low-pressure oil pump and a high-pressure oil pump areintegrated via an oil pump shaft 91 into an oil pump cluster 90, at alower section of the crankcase 20. The low-pressure oil pump feeds oiltowards the internal combustion engine 6, and the high-pressure oil pumpfeeds oil towards the static hydraulic continuously variabletransmission T. The oil pump cluster 90 suctions oil within the oil pan92 by way of the lower section oil strainer 92. The internal combustionengine 6 drives the oil pump cluster 90 via an oil pump drive chain 96engaged on the oil pump shaft drive sprocket 95 installed in thecrankshaft 30, and the oil pump auxiliary drive sprocket 94 insertedinto the oil pump shaft 91. An oil cooler 97 and a low-pressure oilfilter 98 can be seen on the rear section of the crankcase 20. Thehigh-pressure oil filter is installed on the right side of the crankcase20 and is therefore not shown in the drawing.

In FIG. 3, the crankshaft output gear 37, that is installed on the leftend of the crankshaft 30, functions as a gear in combination with thecam type torque damper 38. The crankshaft output gear 37 engages withthe transmission input gear 116 installed on the casing 110 of the tiltplate plunger-type hydraulic pump P of the static hydraulic continuouslyvariable transmission T. The crankshaft output gear 37 and the cam typetorque damper 38 are installed on a collar 60 spline-coupled to thecrankshaft 30. The crankshaft output gear 37 is mounted for freerotation on the collar 60. A recessed cam 37 a with a concave surface inan arc-shape is formed on a side surface of the crankshaft output gear37. A lifter 61 is inserted on the outer circumferential spline of thecollar 60 to allow axial movement. A protruding cam 61 a with anarc-shaped protruding surface is formed on the edge of the lifter 61.The protruding cam 61 a engages with the recessed cam 37 a. A springholder 62 is fastened to the edge of the collar 60 with a spline andcotter pin. A flat spring 63 is installed between the spring holder 62and the lifter 61, and forces the protruding cam 61 a towards therecessed cam 37 a.

During operation at a fixed speed, the torque of the crank shaft 30 istransferred in sequence to the collar 60, the lifter 61, the protrudingcam 61 a, the recessed cam 37 a, and the crankshaft output gear 37. Thecrankshaft output gear 37 rotates along with the crankshaft 30. Whenexcessive torque is applied to the crankshaft 30, the protruding cam 61a slides along the circumference of the cam surface of the recessed cam37 a, and moves axially opposing the force of the flat spring 63,absorbing the huge torque and alleviating the impact.

The crankshaft output gear 37 is a gear for reducing backlash. Thecrankshaft output gear 37 is comprised of a thick, main gear 64 in thecenter, and a thin auxiliary gear 65 supported to allow concentricrotation versus the main gear 64. An auxiliary gear coil spring 66applies a peripheral force via the auxiliary gear 65 on the main gear64. The auxiliary gear 65 applies a circumferential (peripheral) forceto eliminate the backlash gap that occurs between the main gear 64 andthe normal gear, when the backlash reducing gear engages with a normalgear and so can eliminate looseness (play) and alleviate noise to quietthe mechanism. In the present case, the noise from the crankshaft outputgear 37 engaging with the transmission input gear 116 is reduced.

In FIG. 3, the static hydraulic continuously variable transmission T isinstalled rearward of the crankshaft 30. The static hydrauliccontinuously variable transmission T is a device combining a centrifugalgovernor clutch C, tilt plate plunger-type hydraulic pump P, and tiltplate hydraulic motor M via the motor transmission shaft 100. When therotation speed of the casing 110 of the tilt plate plunger-typehydraulic pump P exceeds the specified speed, the transmission inputgear 116 connects (engages) the static hydraulic continuously variabletransmission T due to the centrifugal force effect of the governorclutch C to change the speed. The static hydraulic continuously variabletransmission T changes the speed by changing the speed (gear) ratioaccording to the tilted state of the tilt plate for the tilt platehydraulic motor M. The rotational force for the change in speed isextracted from the motor transmission shaft 100 that rotates as onepiece with the hydraulic pump P and the hydraulic motor M. A motorservomechanism changes the tilt angle of the tilt plate of the tiltplate hydraulic motor M. The structure and effect of the statichydraulic continuously variable transmission T will be described below.

FIG. 4 is a cross-sectional view taken along lines IV-IV in FIG. 2. Thisis the path for transmitting power from the transmission shaft 100 tothe connecting shaft 85. A neutral-drive selector shaft 76 for theneutral-drive selector clutch 75 for selecting the neutral and drivestates, and in parallel with the transmission shaft 100, is supportedvia ball bearings in the right crankcase 20R and the left crankcase 20Lto allow rotation. An output shaft 80 in parallel with the neutral-driveselector shaft 76, is supported via ball bearings in the right crankcase20R and the right crankcase cover 21R to allow rotation. Furthermore,the connecting shaft 85 perpendicular to the output shaft 80, issupported by the connecting shaft support section 84 installed near theleft edge of the output shaft 80 to allow rotation. The connecting shaftsupport section 84 is installed on the outer side of the left crankcase20L (Also see FIG. 2.).

In FIG. 4, a gear 68 is clamped to the transmission shaft 100. A gear 77is inserted into the neutral-drive selector shaft 76 to allow rotationversus the shaft. The gear 77 engages with the transmission output gear65 affixed to the transmission 100. The swing member 78 including a meshgear 78 a and adjacently connected to the gear 77, is inserted to allowsliding axially to the neutral-drive selector shaft 76. Theneutral-drive selector clutch 75 includes the neutral-drive selectorshaft 76, the gear 77, and a swing member 78. The neutral-drive selectorclutch 75 cuts off or connects the drive power conveyed from thetransmission drive shaft 100 to the output shaft 80. When the mesh gear78 a of swing member 78 releases from the gear 77, the neutral-driveselector clutch 75 sets a neutral state, and slides the swing member 78.When the mesh gear 78 a engages with the mesh section of the gear 77,the drive power transmission path is connected, and the drive state isset.

In FIG. 4, a gear 79 is inserted on the neutral-drive selector shaft 76and adjacently contacts the gear 77 on the opposite side of the slidemember 78. A gear 81 is inserted on the right end of the output shaft 80to engage with the gear 79 of neutral-drive selector shaft 76. A bevelgear 82 is formed as one piece with the other end of the output shaft80. A bevel gear 86 is formed as one piece on the front end of theconnecting shaft 85, and engages with the bevel gear 82 of the outputshaft 80. A spline 85 a is mounted on the rear end of the connectingshaft 85 for connection to the rear wheel drive shaft. The rotationaloutput power of the static hydraulic continuously variable transmissionT is transmitted to the rear wheel transmission shaft by way of theseshafts and gears.

FIG. 5 is a vertical cross-sectional view of the static hydrauliccontinuously variable transmission T. The static hydraulic continuouslyvariable transmission T is made up of a tilt plate plunger-typehydraulic pump P, a tilt plate plunger-type hydraulic motor M, and acentrifugal governor clutch C. The transmission shaft 100 functioning asthe output shaft for the static hydraulic continuously variabletransmission T is mounted to pass through the center (of transmissionT). The left end of the transmission shaft 100 is supported to allowrotation by the ball bearings B1, B2 on the left crankcase cover 21L,and the right end is supported to allow rotation by the ball bearing B3on the right crankcase 20R.

The hydraulic pump P includes a pump casing 110 capable of rotatingrelative to the transmission shaft 100 and installed concentrically withit. A pump tilt plate 111 is installed tilted at a specific angle versusthe rotating shaft of the pump casing 110 in the interior of the pumpcasing 110. A pump cylinder 112 is installed facing the pump tilt plate111. Multiple pump plungers 114 are installed to slide within the pumpplunger holes 113 arrayed in a ring shape enclosing the shaft centerwithin the pump cylinder 112. One end of the pump casing 110 issupported to allow rotation by the bearing B2 in the transmission shaft100. The other end is supported to allow rotation by the bearing B4 inthe pump cylinder 112, and also supported to allow rotation by thebearing B1 in the left crankcase cover 21L. The pump tilt plate 111 isinstalled tilted at a specified angle to allow rotation relative to thepump casing 110 by the bearings B5, B6.

The transmission input gear 116 affixed by the bolt 115 is installed onthe outer circumference of the pump casing. The outer end of the pumpplunger 114 engages with the tilt plate surface 111 a of the pump tiltplate 111 protruding outwards, and the inner edge of the pump plunger114 forms a pump fluid chamber 113 a in the pump plunger hole 113. Apump passage opening 117 functioning as a dispensing hole and an intakehole is formed on the edge of the pump plunger hole 113. The pump casing110 rotates when the transmission input gear 116 is made to rotate. Thepump tilt plate 111 installed inside slides along with the rotation ofthe pump casing 110. The pump plunger 114 moves back and forth withinthe pump plunger hole 113 according to the swing of the tilt platesurface 111 a. The hydraulic fluid within the pump fluid chamber 113 ais dispensed and suctioned.

The pump eccentric ring member 118 is installed by a bolt 119 on theright edge of the pump casing 110 in the center of the drawing. Theinner circumferential surface 118 a of the pump eccentric ring member118 is formed in a tubular shape that is off-center versus the rotatingshaft of pump casing 110. Therefore, the inner circumferential surface118 a is also a tubular shape offset in the same way versus the centerline of the transmission shaft 100 and the pump cylinder 112.

The casing 130 of the hydraulic motor M is affixed and supported whileclamped to the right crankcase 20R. The motor casing 130 is formed fromthe spherical member 131 and the elongated member 132, and is clamped bythe bolt 133. A support spherical surface 131 a is formed on the innersurface of the spherical member 131. The hydraulic motor M is comprisedof a motor casing 130, and a motor swing member 134 slide connected andsupported on the support spherical surface 131 a. A motor tilt plate 135is supported to allow rotation by the bearings B7, B8 within the motorswing member 134. A motor cylinder 136 faces the motor tilt plate 135. Amotor plunger 138 installed to allow sliding within the multiple plungerholes 137 passing through in the axial direction and arrayed in a ringshape enclosed the center axis of the motor cylinder 136. The motorcylinder is supported for rotation along the external circumference inthe elongated member 132 of motor casing 130 by way of the bearing B9.The motor swing member 134 is capable of swinging in a movementcentering on the center O extending at a right angle (directionperpendicular to the paper surface) to the center line of thetransmission shaft 100.

The outer side edge of the motor plunger 138 engages with the tilt platesurface 135 a of the motor tilt plate 135 protruding outwards, and theinner side edge of the motor plunger 138 forms a motor fluid chamber 137a within the motor plunger hole 137. A motor passage opening 139functioning as an intake port and a dispensing (exhaust) port for themotor is formed in the edge of the motor plunger hole 137. The edge ofthe motor swing member 134 is formed as an arm 134 a protruding to theouter side and protrudes outwards towards the radius to connect to themotor servo mechanism S. The arm 134 a is controlled by the motor servomechanism S to move left and right, and is controlled to swing centeringon the swing center O of the motor swing member 134. When the motorswing member 134 swings, the motor tilt plate 135 supported ininternally inside it (134) also swings, and changes the angle of thetilt plate.

FIG. 6 is an enlarged cross-sectional view of the vicinity of thedistributor valve 160 of the static hydraulic continuously variabletransmission T. The distributor valve 160 is installed between the pumpcylinder 112 and the motor cylinder 136. The valve body 161 of thedistributor valve 160 is supported between the pump cylinder 112 and themotor cylinder 136, and is integrated with these cylinders by brazing.The motor cylinder 136 is coupled to the transmission shaft 100 by aspline 101. The pump cylinder 112, the distributor valve 160, and themotor cylinder 136 rotate with the transmission shaft 100 as one unit.This integrated pump cylinder 112, valve body 161 of the distributorvalve 160, and the motor cylinder 136 are called the output rotationpiece R. The structure for attaching the output rotation piece R to thetransmission shaft will now be described. A large diameter section 102that is short along the axial length is formed on the outercircumferential side of the transmission shaft 100 corresponding to theleft edge position of the pump cylinder. The left edge surface of thepump cylinder 112 contacts the edge surface of this large diametersection 102, to perform positioning to the left.

The right side positioning of the output rotation piece R, is performedby the stop member 150 installed on the transmission shaft 100 facingthe motor cylinder 136. The stop member 150 includes a cotter pin 151, aretainer ring 152, and a C ring 153. To install the stop member 150, aring-shaped first stop groove 103, and second stop groove 104 are formedacross the outer circumference of the spline 101. A pair of cotter pins151 is separately formed in a semicircular shape shown in FIGS. 7(a) and7(b) and is installed in the first stop groove 103. A retainer ring 152is installed above it as shown in FIGS. 8(a) and 8(b). The tip section152 a of the retainer ring 152 covers the outer circumferential surfaceof the cotter pin 151, and the inward facing flange 152 b of retainerring 152 contacts the side surface of the cotter pin 151. Moreover, theC ring 153 is installed as shown in FIGS. 9(a) and 9(b) in the secondstop groove 104, and prevents the retainer ring 152 from coming loose.As a result of the above, the right edge surface of the motor cylinder136 directly contacts the stop piece 150 and is positioned towards theright.

The output rotation piece R is in this way positioned to the left by thelarge diameter piece 102 via the spline 101. The output rotation piece Ris positioned to the right versus the transmission shaft 100 by the stoppiece 150 and rotates along with the transmission shaft 100 as onepiece. A lubricating oil injection nozzle 152 e connecting the outertilt plate 152 d and the inner circumferential ring groove 152 c of theretainer ring 152 is drilled as three sections along the entirecircumference.

In FIG. 6, the multiple pump side valve holes 162 and motor side valveholes 163 extending towards the diameter and positioned at equal spacesalong the periphery within the valve body 161 forming the distributorvalve 160, are formed in an array of two rows. A pump side switchervalve 164 is installed within the pump side valve hole 162, and a motorside switcher valve 165 is installed within the motor side valve hole163 and each (164, 165) is capable of sliding movement.

The multiple pump side valve holes 162 are formed to correspond to thepump plunger holes 113. Each of the pump side valve holes 162, and pumpflow passages 117 formed in the inner side edge of the pump plungerholes 113, and the multiple pump side connecting passages 166 formed torespectively connect to them (162, 117), are formed in the valve body161. The motor side valve holes 163 are formed to correspond to themotor plunger holes 137. The motor connecting passages 139 formed on theinner edge side of the motor plunger holes 137, and the motor connectingpassages 167 connecting with the respective motor side valve holes 163,are formed in the valve body 161.

A pump side cam ring 168 is installed at a position enclosing the outercircumferential edge of the pump side switcher valve 164 on thedistributor valve 160. A motor side cam ring 169 is installed at aposition enclosing the outer circumferential edge of the motor sideswitcher valve 165 on the distributor valve 160. The pump side cam ring168 is installed onto the inner circumferential surface 118 a of pumpeccentric ring member 118 clamped by a bolt 119 to the tip of the pumpcasing 110 (FIG. 5). The motor cam ring 169 is installed onto the innercircumferential surface 140 a of the motor eccentric ring member 140positioned in contact with the tip of the elongated member 132 of motorcasing 130 (FIG. 5). The outer side edge of the pump side switcher valve164 on the inner circumferential surface of the pump side cam ring 168is engaged to allow sliding movement via the pump side restrictor ring170. The outer side edge of the motor side switcher valve 165 on theinner circumferential surface of the motor side cam ring 169 is engagedto allow sliding movement via the motor side restrictor ring 171. Thecam ring and the restrictor ring are both capable of relative rotationon either the pump side or the motor side.

A ring-shaped recess functioning as the inner side passage 172 is carvedonto the outer circumferential surface of the transmission shaft 100facing the inner circumferential surface of the valve body 161. Theinner edge of the motor side valve hole 163 and the pump side valve hole162 are connected to this inner side passage 172. An outer side passage173 is formed near the external circumference of the valve body 161 toconnect with the pump side valve hole 162 and motor side valve hole 163.

The operation of the distributor valve 160 will now be described. Whenthe drive force of the internal combustion engine is conveyed to thetransmission input gear 116 and the pump casing 110 rotates, the pumptilt plate 111 swings according to that rotation. The pump plunger 114engaging with the tilt plate surface 111 a of the pump tilt plate 111moves axially back and forth within the pump plunger hole 113 by way ofthe swinging of the pump tilt plate 111. Hydraulic fluid is dispensedvia the pump passage opening 117 from the pump fluid chamber 113 aduring inward movement of the pump plunger 113, and hydraulic fluid issuctioned into the pump fluid chamber 113 a via the pump passage opening117 during outward movement.

At this time, the pump side cam ring 168 installed on the innercircumferential surface 118 of the pump eccentric ring member 118coupled to the edge of the pump casing 110, rotates along with the pumpcasing 110. The pump side cam ring 168 is offset (eccentric) versus therotation center of the pump casing 110. In other words, it is installedoffset (eccentric) to the valve body so that the pump side switchervalve 164 moves back and forth along the diameter within the pump sidevalve hole 112, according to the rotations of the pump side cam ring168.

The pump side switcher valve 164 moves back and forth in this way, andwhen moving inwards along the diameter within the valve body 161, thepump side connecting passage 166 opens outwards along the diameter via asmall diameter section 164 a of the pump side switcher valve 164, andconnects the pump passage opening 117 and the outer side passage 173.When the pump side switcher valve 164 moves outward along the diameterwithin the valve body 161, the pump side connecting passage 166 opensinwards along the diameter, and connects the pump passage opening 117and the inner side passage 172.

The pump tilt plate 111 swings along with the rotation of the pumpcasing 110, the pump side cam ring 168 moves the pump side switchervalve 164 back and forth along the diameter, to match the position(lower dead point) where the pump plunger 114 is pressed farthest to theoutside, and the position (upper dead point) where furthermost to theinside during its back and forth movement. The pump plunger 114consequently moves from the lower dead point to the upper dead pointalong with the rotation of the pump casing 110, and the hydraulic fluidwithin the pump fluid chamber 113 a is dispensed from the pump passageopening 117. The pump passage opening 117 at this time is connected tothe outer side passage 173 so that the hydraulic fluid is sent to theouter side passage 173. On the other hand, when the pump plunger 114moves from the upper dead point to the lower dead point along with therotation of the pump casing 110, the hydraulic fluid within the innerside passage 172 is suctioned inside the pump fluid chamber 113 a viathe pump passage opening 117. In other words, when the pump casing 110is driven, hydraulic fluid is dispensed from a pump fluid chamber 113 aon one side and supplied to the outer side passage 173, and hydraulicfluid is suctioned from the inner side passage 172 into the pump fluidchamber 113 a on the other side of the transmission shaft 100.

However, the motor side cam ring 169 installed on the innercircumferential surface 140 a of the motor ring eccentric member 140positioned in sliding contact on the edge of the motor casing 130, ispositioned eccentrically versus the rotation center of the transmissionshaft 100 and the output rotation piece R, and motor cylinder 136, whenthe motor ring eccentric member 140 is in the usual position, When themotor cylinder 136 rotates, the motor side switcher valve 165 moves backand forth along the diameter within the motor side valve hole 163according to that (136) rotation.

When the motor side switching valve 165 moves inwards along the diameterwithin the valve body 161, the small diameter section 165 a of the motorside switching valve 165 opens the motor side connection path 167 to theoutside, connecting the motor passage opening 139 and the outer sidepassage 173. When the motor side switching valve 165 moves outward alongthe diameter within the valve body 161, the motor side connection path167 opens inwards along the diameter, connecting the motor passageopening 139 and the inner side passage 172.

The hydraulic fluid dispensed from the hydraulic pump P is sent to theouter side passage 173, and this hydraulic fluid is supplied via themotor side connection path 167, and the motor passage opening 139 toinside the motor fluid chamber 137 a, and the motor plunger 138 ispressed axially outward. The outer edge of the motor plunger 138 isconfigured to slide-contact to the section where the motor tilt plate135 moves from the upper dead point to the lower dead point. Due to thisforce pressing axially outwards, the motor plunger 138 moves along withthe motor tilt plate 135, along the tilted surface formed by the motorsliding member 134 and the bearing B7, B8. The motor cylinder 136 isconsequently pressed by the plunger 138 and driven. Along with therotation of the motor cylinder 136, the motor side cam ring 169 makesthe motor side switching valve 165 move back and forth along thediameter in the valve body 161, corresponding to the back and forthmovement of the motor plunger 138.

The motor cylinder 136 on the opposite side, moves the periphery of thetransmission shaft 100 along with the rotation of the motor tilt plate135 centering on the transmission shaft 100, moving from the lower deadpoint to the upper dead point, and the hydraulic fluid within the motorfluid chamber 137 a is sent from the motor passage opening 139 to theinner side passage 172, and is suctioned via the pump side connectingpassages 166 and pump passage opening 117.

A hydraulic shut off circuit joining the tilt plate hydraulic motor Mand the tilt plate plunger-type hydraulic pump P is in this way formedby the distributor valve 160. The hydraulic fluid dispensed according tothe rotations of the hydraulic pump P is sent to the hydraulic motor Mvia the other hydraulic shut-off circuit (outer side passage 173),driving it. Moreover, the hydraulic fluid dispensed along with therotation of the hydraulic motor M is returned to the hydraulic pump Pvia the other hydraulic shut-off circuit (inner side passage 172).

In the static hydraulic continuously variable transmission T describedabove, the hydraulic pump P is driven by the internal combustion engine6, the rotation drive power of the hydraulic motor M is converted by thedistributor valve 160 and the hydraulic motor M, extracted from thetransmission shaft 100, and transmitted to the vehicle wheels. When thevehicle is being driven, the outer side passage 173 is the high pressureside fluid path, and the inner side passage 172 is the low pressureside. On the other hand, during times such as driving downhill, thedrive force for the vehicle wheels is transmitted from the transmissionshaft 100 to the hydraulic motor M, and the rotational drive force ofthe hydraulic motor P renders the effect of an engine brake conveyed tothe internal combustion engine 6, the inner side passage 172 is the highpressure side fluid path, and the outer side passage 173 is the lowpressure side fluid path.

The gear ratio of the static hydraulic continuously variabletransmission T can be continuously changed by varying the tilt angle ofthe motor swing member 134. The tilt angle of the motor swing member 134is changed for a motor tilt plate angle of zero or in other words, whenthe motor tilt plate is perpendicular to the transmission shaft, the topgear ratio is reached, the amount of offset (eccentricity) of theeccentric (ring) member 140 reaches zero due to the effect of the lockupactuator A (FIG. 5), the center of the motor cylinder 136 matches thecenter of the eccentric member 140, and the pump casing 110, the pumpcylinder 112, the motor cylinder 136, and the transmission shaft 100rotates as one unit to efficiently transfer the drive power.

FIG. 10 is a vertical cross-sectional view of the vicinity of thecentrifugal governor clutch C. When the inner side passage 172 and theouter side passage 173 are connected in the static hydrauliccontinuously variable transmission T, the high hydraulic pressure is nolonger applied, and drive power is no longer transmitted between thehydraulic pump P and the hydraulic motor M. In other words, clutchcontrol is implemented by controlling the degree of opening of theconnection between the inner side passage 172 and the outer side passage173.

The centrifugal governor clutch C includes a spring sheet member 182 anda cam plate member 181 clamped by a bolt 180 to the edge of the pumpcasing 110. A roller 183 is held respectively within the multiple camplate grooves 181 a formed extending diagonally along the diameter onthe inner surface of the cam plate member 181. A pressure plate 184includes an arm section 184 a facing the cam plate groove 181 a. A coilspring 185 with one end supported by the spring sheet member 182 and theother end acting on the pressure plate 184 makes the arm section 184 aof the pressure plate 184 apply a pressing force on the inside of thegroove 181 a. A slide shaft 186 slides along the axial line of thetransmission shaft and inserted into the center hole 181 b of the camplate member 181 and also passes through the center section of thepressure plate 184. A rod-shaped clutch valve 187 engaged with theclutch valve engage section 186 a of the slide shaft 186. One end of thecoil spring 185 is supported by the spring sheet 182 a formed on theinner-facing flange of the spring sheet member 182. The pressure plate184 and the slide shaft 186 are both fabricated as separate pieces, andthen coupled into a single piece to comprise the roller bearing member188. The pressure plate 184 is fabricated by forming it in a press, andthe slide shaft 186 is fabricated by cutting with machining tools andboth parts are then welded together into one piece.

When the pump casing 110 is in a static state, or in other words a statewhere neither the cam plate member 181 or the spring sheet member 182are rotating, the arm section 184 a presses the roller 183 into the camplate groove 181 a by the pressing force applied to the pressure plate184 by the coil spring 185. The cam plate groove 181 a is in a tiltedstate so that the roller 183 is pressed along the diameter of the camplate member 181, and the pressure plate 184, and the swing axis 186integrated with it, and the rod clutch valve 187 engaged in the swingshaft 186 are in a state shifted to the left.

When the pump casing 110 is driven by the rotation of the transmissioninput gear 116 (FIG. 5), and the cam plate 181 and the spring sheetmember 182 rotate, the roller plate 183 is pressed back along the tiltedsurface of the cam plate member 181 outwards along the diameter bycentrifugal force, and presses the arm section 184 a to the right andthe pressure plate 184 moves to the right while opposing the force ofthe coil spring 185. The amount of movement towards the right of thepressure plate 184 and the slide shaft 186 functioning as one piece withit are determined by the centrifugal force acting on the roller 183. Inother words, it (amount of movement) is determined according to therotational speed of the pump casing 110. When the rotational speed ofthe pump casing 110 increases, the rod clutch valve 187 engaged in theslide shaft 186, extends along the inner section of the transmissionshaft 100, and shifts to the inner part of the clutch valve hole 105.The centrifugal governor mechanism is in this way configured to apply acentrifugal force to the roller 183 by utilizing the centrifugal forcefrom the rotation of the pump casing.

An inner side connecting fluid path 190 is formed in the transmissionshaft 100 as shown in FIG. 10 that joins the clutch valve hole 105 andthe inner side passage 172. An outer side connecting fluid path 191joining the clutch valve hole 105 and an outer side passage 173, and aring-shaped groove 192 and a tilt fluid path 193 for a short connectionare formed in the transmission shaft 100 and the pump cylinder 112. Whenthe pump casing 110 is in a static state, the inner side connectingfluid path 190 and the outer side connecting fluid path 191 areconnected by way of the small diameter section 187 a of the rod-shapedclutch valve 187, and consequently the inner side passage 172 and outerside passage 173 are connected so the clutch is disengaged.

When the pump casing rotation exceeds the specified speed, and therod-shaped clutch valve 187 shifts to the innermost section of theclutch valve hole 105 due to effect of centrifugal force from thegovernor mechanism, the small diameter section 187 a of the rod-shapedclutch valve 187 releases (away) from the opening on the clutch valvehole 105 side of the outer side connecting fluid path 191. The outerside connecting fluid path 191 opening is blocked by the large diameterside surface 187 b of rod-shaped clutch valve 187 (See position ofrod-shaped clutch valve 187 in FIG. 6.). The connection between theinner side passage 172 and outer side passage 173 is therefore blockedand an oil circulation shut-off circuit is formed from the hydraulicpump P and outer side passage 173 and hydraulic motor M and inner sidepassage 172, and the static hydraulic continuously variable transmissionT functions. Switching from a clutch released state to a clutch engagedstate is performed by the roller so that the clutch gradually becomesengaged (connected) according to this movement.

FIG. 11 is a vertical cross-sectional view of an essential section ofthe static hydraulic continuously variable transmission T showing thesupply path for the lubricant fluid and the operating (hydraulic) fluid.The operating (hydraulic) fluid is supplied from the high-pressure oilpump of the oil pump cluster 90 driven by the internal combustionengine, via the fluid path within the crankcase, from the right end, tothe transmission shaft center fluid path 200 formed along the axis andin the center of the transmission shaft 100. The innermost section ofthe transmission shaft center fluid path 200 is joined to the fluid path201 extending along the diameter to the outer circumference. The fluidpath 201 is also joined with the output rotation piece inner fluid path202 formed in parallel with the transmission shaft 100 within the outputrotation piece R (motor cylinder 136, valve body 161, pump cylinder 112)that rotates as one piece with the transmission shaft 100. The outputrotation piece inner fluid path 202 is a fluid path including the fluidpath 202 a within the motor cylinder 136, the fluid path 202 b withinthe valve body 161, and the fluid path 202 c within the pump cylinder112.

A check valve 210 for supplying replacement fluid within the outer sidepassage 173 is installed within the pump cylinder 112. The outputrotation piece inner fluid path 202 is joined to the check valve 210 viathe fluid path 203 facing outwards along the diameter in the innermostsection (202), and if necessary (according to leakage of operating fluidfrom the hydraulic shut-off circuit), operating fluid is supplied to theouter side passage 173 of the valve body 161. A check valve and fluidpath for supplying operation fluid to the inner side passage 172 areinstalled in the same way in another section of the pump cylinder 112,and if necessary also supply operating fluid to the inner side passage172 (omitted from drawing).

An outer ring groove 204 is formed on the outer circumference of thetransmission shaft 100 corresponding to the innermost section of theoutput rotation piece inner fluid path 202, and connects to theinnermost section of the output rotation piece inner fluid path 202. Aninner ring groove 205 is formed on the inner circumference of the clutchvalve hole 105 of the transmission shaft 100, and connects to the outerring groove 204 at one location via the connecting fluid path 206. Anorifice 206 a is formed in the connecting fluid path 206. On thetransmission shaft 100, a lubricant oil injection nozzle 207 connectingto the inner ring groove 205 of the clutch valve hole and facing theexternal circumference of the transmission shaft 100 is drilled at threelocations on the transmission shaft periphery. A portion of the oilsupplied within the output rotation piece inner fluid path 202 isinjected by way of the lubricant oil injection nozzle 207, and the outerring groove 204, the connecting fluid path 206, the inner ring groove205, and lubricates the pump tilt plate 111, etc.

A fluid path 208 is formed at one location from the transmission shaftcenter fluid path 200 along the diameter, facing towards the stop member150 on the right edge positioner section of the output rotation piece Ron the transmission shaft 100, and an orifice 208 a is formed on itsinner edge section. The outer edge section of the fluid path 208connects along the diameter to the ring groove 152 c formed on the innercircumference of the retainer 152. A portion of the oil supplied toinside the transmission shaft fluid path 200 is supplied via the fluidpath 208 and the inner ring groove 152 c, to the lubricant oil injectionnozzle 152 e formed at three locations on the periphery of the innerring groove 152 c and the outer tilt plate 152 d of the retainer ring152; and is dispensed from the lubricant oil injection nozzle 152 e andlubricates the motor tilt plate 135, etc.

In FIG. 11, the distance L1 between the inner edge surface 113 b of thepump plunger hole 113 and the pump side edge 161 a of the valve body161, is made large compared to the distance L2 between the inner edgesurface 137 b of the motor plunger hole 137 and the motor side surface161 b of the valve body 161. The larger distance is required because itis necessary to form a tilt fluid path 193 (FIG. 10) joining the clutchvalve hole 105 and the outer side passage 173 between the inner edgesurface 113 b of the pump plunger hole 113 of pump cylinder 112 and pumpside edge 161 a of the valve body 161 on the pump side; and thereforethe pump plunger hole 113 are separated from the valve body 161. Thereis no need to form a tilt fluid path on the (other) motor M side andtherefore the distance between the inner edge surface 137 b of the motorplunger hole 137 and the motor side surface 161 b of the valve body 161is small.

The above-mentioned lubricating structure for a static hydrauliccontinuously variable transmission gives the following effects:

(1). Only part of an oil path in a direction of the shaft diameter of isan orifice. Therefore, the transmission of the present invention iseasier to manufacture compared to a lubrication oil ejection hole in aconventional transmission. Since the lubrication oil ejection hole thathas an amount of oil controlled by the orifice is provided away from theoil path whose, freedom in the setting of an angle, direction, number,etc. of the holes, and the lubricity of theswash plate, etc. isimproved. The lubrication oil ejection hole haing a small diameter isprovided in a thin retainer, and so it is easy to manufacture.

(2). An orifice for adjusting the amount of oil is located at one place.Therefore, the orifice diameter is enlarged, and workability and oilamount controllability are improved. Since a lubrication oil ejectionhole can be provided, communicating with a ring oil path in acircumferential direction, plural lubrication oil ejection holes caneasily be provided.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

1. A lubricating structure for a static hydraulic continuously variabletransmission, wherein a hydraulic circuit comprised of a high pressurehydraulic path for feeding working oil from a hydraulic pump to ahydraulic motor and a low pressure hydraulic path for feeding workingoil from the hydraulic motor to the hydraulic pump is located betweensaid hydraulic pump and said hydraulic motor, and a cylinder member thatstores the hydraulic pump and the hydraulic motor is fixed to a shaft ofthe transmission by a cotter pin and a retainer for depressing saidcotter pin, said lubricating structure comprising: a central oil pathaxially formed at a center of the shaft of the transmission; acircumferential oil path formed between an inner circumferential part ofthe retainer and an outer circumferential part of the shaft of thetransmission; a diametrical oil path in communication with saidcircumferential oil path and said central oil path, said diametrical oilpath being provided with an orifice; and a lubricant oil ejection holearranged at the retainer to eject lubricant oil from saidcircumferential oil path.
 2. The lubricating structure for a statichydraulic continuously variable transmission according to claim 1,wherein said orifice is in communication with said central oil path. 3.The lubricating structure for a static hydraulic continuously variabletransmission according to claim 2, wherein said circumferential oil pathforms an annular shape.
 4. The lubricating structure for a statichydraulic continuously variable transmission according to claim 3,wherein said lubricating structure includes one diametrical oil path incommunication with said circumferential oil path and said central oilpath and a plurality of said lubricant oil ejection holes.
 5. Thelubricating structure for a static hydraulic continuously variabletransmission according to claim 4, wherein there are three of saidlubricant oil ejection holes formed in the retainer.
 6. The lubricatingstructure for a static hydraulic continuously variable transmissionaccording to claim 1, further comprising a diametrical oil pathextending from said central oil path to a fluid path formed in an outputrotation piece on an outside of the shaft of the transmission, saidfluid path formed in the output rotation piece extending in parallel tosaid central oil path.
 7. The lubricating structure for a statichydraulic continuously variable transmission according to claim 6,wherein the output rotation piece includes the cylinder member, a motorcylinder and a valve body, and said fluid path formed in the outputrotation piece extends through the cylinder member, the motor cylinderand the valve body.
 8. The lubricating structure for a static hydrauliccontinuously variable transmission according to claim 7, wherein thecylinder member includes a check valve installed therein, said fluidpath formed in the output rotation piece being in communication with thecheck valve by a diametrically extending fluid path.
 9. A lubricatingstructure for a static hydraulic continuously variable transmission,comprising: a transmission shaft, said transmission shaft including acentral oil path axially formed at a center thereof; a retainer mountedon an outer circumference of said transmission shaft, a circumferentialoil path being formed between an inner circumferential part of theretainer and outer circumference of said transmission shaft; a radiallyextending oil path, said radially extending oil path being formed insaid transmission shaft and being in communication with saidcircumferential oil path and said central oil path, said radiallyextending oil path being provided with an orifice; and a lubricant oilejection hole, said lubricant oil ejection hole being formed through anouter surface of said retainer and being in communication with saidcircumferential oil path to eject lubricant oil from saidcircumferential oil path.
 10. The lubricating structure for a statichydraulic continuously variable transmission according to claim 9,wherein said orifice is in communication with said central oil path. 11.The lubricating structure for a static hydraulic continuously variabletransmission according to claim 10, wherein said circumferential oilpath forms an annular shape.
 12. The lubricating structure for a statichydraulic continuously variable transmission according to claim 11,wherein said lubricating structure includes one diametrical oil path incommunication with said circumferential oil path and said central oilpath and a plurality of said lubricant oil ejection holes.
 13. Thelubricating structure for a static hydraulic continuously variabletransmission according to claim 12, wherein there are three of saidlubricant oil ejection holes formed in the retainer.
 14. The lubricatingstructure for a static hydraulic continuously variable transmissionaccording to claim 9, further comprising a diametrical oil pathextending from said central oil path to a fluid path formed in an outputrotation piece on an outside of the transmission shaft, said fluid pathformed in the output rotation piece extending in parallel to saidcentral oil path.
 15. The lubricating structure for a static hydrauliccontinuously variable transmission according to claim 14, wherein theoutput rotation piece includes a cylinder member, a motor cylinder and avalve body, and said fluid path formed in the output rotation pieceextends through the cylinder member, the motor cylinder and the valvebody.
 16. The lubricating structure for a static hydraulic continuouslyvariable transmission according to claim 15, wherein the cylinder memberincludes a check valve installed therein, said fluid path formed in theoutput rotation piece being in communication with the check valve by adiametrically extending fluid path.